Troubleshooting Jobs¶
How do I find which Slurm accounts I am part of?
You can use the iris
command line interface to Iris to retrieve user details. The first column Project is all the Slurm accounts a user is associated with.
In this example, the current user is part of two accounts nstaff
and m3503
.
$ iris
Project Used(user) Allocated(user) Used Allocated
--------- ------------ ----------------- ---------- -----------
m3503 0.0 1000000.0 12726.1 1000000.0
nstaff 21690.5 4000000.0 26397725.1 80000000.0
What is my default Slurm account?
You can find the default user account by logging into https://iris.nersc.gov and navigate to CPU tab, you will see a column Default
that shows your default Slurm account. In this example, the user default account is nstaff
which means that user job will be charged to nstaff
account even if they do not specify #SBATCH -A
in their job script.
My job will terminate because it will exceed queue run time limit, what can I do?
If your job terminates due to queue run limit, you have a few options:
- Optimize your workflow by profiling your code. We have several profiling tools including HPCToolkit, CrayPAT, MAP, Intel VTune, Parallelware Trainer. For more details on profilers see performance tools page
- Increase Node/Processor count to reduce runtime.
- Utilize checkpoint/restart via DMTCP
- If all else fails, request a reservation
What is a Slurm multi-cluster mode?
At Cori, we have configured Slurm in Multi-Cluster mode with two clusters cori
and escori
. Each Slurm cluster is independent, with its own Slurm environment (partitions/qos) and job accounting.
When you login to Cori, your default cluster is cori
, and you can run jobs to Slurm cluster via sbatch --clusters=cori
or sbatch --clusters=escori
.
In order to submit jobs to escori
Slurm cluster you need to load the following module:
module load esslurm
Note
module load esslurm
will make escori
your default Slurm cluster. If you want to revert back to cori
unload the module (module unload esslurm
).
The default Slurm binaries are in /usr/bin
but we place Slurm binaries for esslurm (i.e., sbatch
, squeue
, sacct
, srun
) in /opt/esslurm/bin
. Once you load the module your sbatch
should be the following:
cori$ which sbatch
/opt/esslurm/bin/sbatch
How do I monitor a job that I submitted?
If you want to monitor your jobs please use squeue
, or sacct
and see monitoring page for more details. Please note that the jobID's are unique to the Slurm cluster (cori
, escori
), for instance if you submit a job to xfer
queue your job will be routed to the escori
Slurm cluster and you will need to use squeue --clusters=escori
or sacct --clusters=escori
to monitor the job.
Unable to submit jobs to premium queue?
You need to login to https://iris.nersc.gov and confirm your account has access to premium
queue. If you are a PI please see Enabling the premium QOS and grant your colleague access to premium
queue. If you are not a PI, please contact your PI to add your username to queue. This change will take up to an hour to propagate to our systems.
Shown below is a snapshot from iris to enable premium queue access. Please note this is granted per project (#SBATCH -A <account>
).
Why is my job marked as InvalidQOS
?
This indicates you have specified incorrect qos name #SBATCH -q <QOS>
in your job-script. Please check our queue policy for list of available queues and correct your job script.
If your account incurs a negative balance, your project will be restricted to overrun and xfer queue. Take for example, project m0001
has a negative balance since it used 75,000 node hours whereas the project limit was 50,000. We can check this using iris
command.
cori$ iris
Project Used(user) Allocated(user) Used Allocated
--------- ------------ ----------------- --------- -----------
m0001*** 750000.0 50000.0 750000.0 50000.0
* = user share of project Negative
** = project balance negative
*** = user and project balance negative
Due to this change, project m0001
will be restricted to subset of queues, if you have previously run jobs on default queues (debug
, flex
, regular
), your jobs will be stuck indefinitely and you should consider killing the jobs using scancel.
Why is my job queued for so long?
The most common cause is that the job requested a long walltime limit: queue wait time correlates strongly with walltime request and weakly with number of nodes (until you reach about half the machine).
The reason for this is the way that jobs are scheduled. Every 5-7 minutes, Slurm makes a plan about what jobs it's going to run for the next 96 hours. It assembles this schedule by going down the list of jobs in priority order, and inserting each into the first empty slot in which it fits. After making that schedule, Slurm scans down the list of jobs not on the schedule, and tries to determine whether it can start each job right now, without having to change anything in its schedule. In other words, it looks for jobs to fill gaps at the front of the schedule. This is why jobs submitted after yours in the regular queue might start before your jobs.
The characteristics of jobs that are able to fit into those gaps are uniformly that they request a relatively short walltime (generally 4 hours or less; less is better). Until your node count gets up to about half the machine, the number of nodes is not correlated with wait time; it is almost exclusively related to the length of the walltime request.
So, if you can arrange your jobs to use higher node counts for less time (e.g., 48 nodes for 2 hours rather than 2 nodes for 48 hours), they will be more likely to fit into those gaps in the schedule. Another option (for applications that are able to use it) is checkpoint/restart. This also allows you to run your job in the flex queue, which offers a substantial discount. If your application doesn't directly support checkpointing, you may still be able to checkpoint it with DMTCP.
Cannot Submit Jobs¶
If you are unable to submit jobs we recommend you check the following
- Check your job script for error (invalid qos name, missing time-limit, invalid node count or cpu count, etc...)
- Check the MOTD and see if Cori is online. See https://my.nersc.gov/
- Check NERSC outage calendar for scheduled outage
- Check Queue Policy to ensure your job complies with Slurm policies
- Check if you have
esslurm
module loaded, this exposes different Slurm binaries. Unloading this module will solve many of your errors.- If you are submitting jobs to
xfer
,compile
,bigmem
queue, check that you haveesslurm
module loaded - For any other cori jobs, ensure that the
esslurm
module is not loaded
- If you are submitting jobs to
- If you are having issues with Cori GPU jobs then please see Cori GPU Documentation.
- Check your startup configuration files
~/.bashrc
and~/.bashrc.ext
for any user environmentPATH
,LD_LIBRARY_PATH
, modules, or aliases that may impact your shell. - Check if you are charging to correct account (
-A <Account>
). If you are not sure of your project code you can runiris
or login to https://iris.nersc.gov/ - Check if you have negative balance for your project, if so please contact your project PI. You can run
iris
to see your project details. - Check your file system quota using
showquota
, if your account exceeds quota limit you won't be able to submit jobs.
If all else fails please submit a ticket at http://help.nersc.gov/ with the following details:
- Job Script and/or Slurm command
- Output of
module list
- Output of warning/error messages
- Time when command was run (use
date
command) - Add any attachments necessary to troubleshoot issue
Common Errors With Jobs¶
Some common errors encountered during submit or run times and their possible causes are shown in the following table.
Job submission errors¶
-
Error message:
sbatch: error: Your account has exceeded a file system quota and is not permitted to submit batch jobs. Please run `myquota` for more information.
Possible causes/remedies:
Your file system usage is over the quota(s). Please run the
showquota
command to see which quota is exceeded. Reduce usage and resubmit the job. -
Error message:
sbatch: error: Job request does not match any supported policy. sbatch: error: Batch job submission failed: Unspecified error.
Possible causes/remedies:
There is something wrong with your job submission parameters and the request (the requested number of nodes, the walltime limit, etc.) does not match the policy for the selected qos. Please check the queue policy.
This error also happens when the job submission didn't include the
--time-min
line with theflex
.If you also have access to Cori GPU nodes, make sure to unload the
cgpu
module before trying to submit jobs to Cori Haswell or KNL nodes. -
Error message:
sbatch: error: More resources requested than allowed for logical queue shared (XX requested core-equivalents > YY) sbatch: error: Batch job submission failed: Unspecified error
Possible causes/remedies:
The number of logical cores that your job tries to use exceeds the the number that you requested for this
shared
qos job. -
Error message:
Job submit/allocate failed: Unspecified
Possible causes/remedies:
This error could happen if a user has no active NERSC project on Cori. Please make sure your NERSC account is renewed with an active allocation.
-
Error message:
Job submit/allocate failed: Invalid qos specification
Possible causes/remedies:
This error mostly happens if a user has no access to certain Slurm qos. For example, a user who doesn't have access to the
realtime
qos would see this error when submitting a job to the qos. -
Error message:
sbatch: error: Batch job submission failed: Socket timed out on send/recv operation
Possible causes/remedies:
The job scheduler is busy. Some users may be submitting lots of jobs in a short time span. Please wait a little bit before you resubmit your job.
This error normally happens when submitting a job, but can happen during runtime, too.
-
Error message:
cori$ salloc ... --qos=interactive salloc: Pending job allocation XXXXXXXX salloc: job XXXXXXXX queued and waiting for resources salloc: error: Unable to allocate resources: Connection timed out
Possible causes/remedies:
The interactive job could not start within 6 minutes, and, therefore, was cancelled. It is because either the number of available nodes left from all the reserved interactive nodes or out of the 64 node limit per NERSC project was less than what you requested. See our Cori "interactive" QOS policy page for more details.
-
Error message:
sbatch: error: No architecture specified, cannot estimate job costs. sbatch: error: Batch job submission failed: Unspecified error
Possible causes/remedies:
Your job didn't specify the type of compute nodes. To run on Haswell nodes, add to your batch script:
#SBATCH -C haswell
To request KNL nodes, add this line:
#SBATCH -C knl
-
Error message:
sbatch: error: The overrun logical queue requires an lower balance than the estimated job cost. Job cost estimated at XX.XX NERSC-Hours, your balance is YYYYYY.YY NERSC-Hours (Repo: YYYYYYY.YY NERSC-Hours). Cannot proceed, please see https://docs.nersc.gov/jobs/policy/ for your options to run this job. sbatch: error: Batch job submission failed: Unspecified error
Possible causes/remedies:
You submitted the job to the
overrun
partition directly. When you submit a job with a normal qos (e.g.,regular
,debug
, etc.), requesting more NERSC-Hours than your NERSC project balance, it will be automatically routed to theoverrun
queue. -
Error message:
sbatch: error: No available NERSC-hour balance information for user xxxxx, account yyyyy. Cannot proceed. sbatch: error: Batch job submission failed: Unspecified error
Possible causes/remedies:
You submitted the job using a project that you are not allowed to use. Login in to Iris to see which NERSC project you can use.
-
Error message:
sbatch: error: Batch job submission failed: Unable to contact Slurm controller (connect failure)
Possible causes/remedies:
There may be an issue with Slurm. If the error is still seen after a few minutes, report to NERSC.
-
Error message:
sbatch: error: Job cost estimated at XXXXXXXX.XX NERSC-Hours, your balance is XXXXXXX.XX NERSC-Hours (Repo: XXXXXXXX.XX NERSC-Hours). Cannot proceed, please see https://docs.nersc.gov/jobs/policy/ for your options to run this job. sbatch: error: Job submit/allocate failed: Unspecified error
Possible causes/remedies:
Your remaining NERSC project balance is not big enough to run the job.
-
Error message:
srun: error: Unable to create step for job XXXXXXXX: More processors requested than permitted
Possible causes/remedies:
Your
srun
command required more logical cores than available. Please check the values for the-n
,-c
, etc.
Runtime errors¶
-
Error message:
srun: error: eio_handle_mainloop: Abandoning IO 60 secs after job shutdown initiated.
Possible causes/remedies:
Slurm is giving up waiting for stdout/stderr to finish. This typically happens when some rank ends early while others are still wanting to write. If you don't get complete stdout/stderr from the job, please resubmit the job.
-
Error message:
Tue Jul 17 18:04:24 2018: [PE_3025]:_pmi_mmap_tmp: Warning bootstrap barrier failed: num_syncd=3, pes_this_node=68, timeout=180 secs
Possible causes/remedies:
Use the
sbcast
command to transmit the executable to all compute nodes before ansrun
command. For more information onsbcast
, see our best practices for large jobs. -
Error message:
slurmstepd: error: _send_launch_resp: Failed to send RESPONSE_LAUNCH_TASKS: Resource temporarily unavailable
Possible causes/remedies:
This situation does not affect the job. This issue may have been fixed.
-
Error message:
srun: fatal: Can not execute vasp_gam /var/spool/slurmd/job15816716/slurm_script: line 17: 34559 Aborted srun -n 32 -c8 --cpu-bind=cores vasp_gam
Possible causes/remedies:
The user does not belong to a VASP group. The user needs to provide VASP license info following the instructions.
-
Error message:
cori$ sqs JOBID ST ... REASON XXXXXXXX PD ... Nodes required* ...
or
cori$ scontrol show job XXXXXXXX ... JobState=PENDING Reason=Nodes_required_for_job_are_DOWN,_DRAINED_or_reserved_for_jobs_in_higher_priority_partitions Dependency=(null) ...
Possible causes/remedies:
The job was tentatively scheduled to start as a backfill job. But some of the assigned nodes are now down, drained or re-assigned to a higher priority job. Wait until Slurm reschedules the job.
-
Error message:
srun: Job XXXXXXXX step creation temporarily disabled, retrying
Possible causes/remedies:
This often happens when there are many
srun
commands in a batch job and compute nodes are not fully completed from the lastsrun
before the next one starts. Usually the next job step starts eventually.However, if you observe a significant delay with starting a
srun
command, the problem may have to be examined by NERSC staff. In that case, please report the problem to us. Length of the delay, however, can depend on resources (memory, threads, I/O, etc.) involved in the last job step. -
Error message:
srun: error: Unable to create step for job XXXXXXXX: Job/step already completing or completed
which appears with or without this message:
srun: Job XXXXXXXX step creation temporarily disabled, retrying
Possible causes/remedies:
This may be caused by a system issue. Please report to NERSC.
-
Error message:
Tue Sep 18 20:13:26 2018: [PE_5]:inet_listen_socket_setup:inet_setup_listen_socket: bind failed port 63725 listen_sock = 4 Address already in use Tue Sep 18 20:13:26 2018: [PE_5]:_pmi_inet_listen_socket_setup:socket setup failed Tue Sep 18 20:13:26 2018: [PE_5]:_pmi_init:_pmi_inet_listen_socket_setup (full) returned -1 ...
Possible causes/remedies:
Typically this error indicates that multiple applications have been launched on the same node, and both are using the same PMI (Process Management Interface, which supports launching and managing the processes that make up the execution of a parallel program; see the
intro_pmi
man page for more info) control port number. When running multiple applications per node, it is the launcher's responsibility to provide PMI with a new (available) port nuber by setting thePMI_CONTROL_PORT
env variable. Slurm typically does this.You can try either of the following approaches to suppress the PMI errors because your code runs on a single node and does not communicate between nodes:
-
Recompile your code with the
craype-network-aries
module unloaded, then the PMI library will not be linked into your code:cori$ module swap craype-network-aries craype-network-none
-
Set the fowllowing two env variables:
cori$ export PMI_NO_FORK=1 cori$ export PMI_NO_PREINITIALIZE=1
-
-
Error message:
/some/path/ ./a.out error while loading shared libraries: /opt/gcc/7.3.0/snos/lib64/libgomp.so.1: cannot read file data: Input/output error ...
Possible causes/remedies:
A possible cause is that the
LD_LIBRARY_PATH
environment varialbe has been modified. Sincelibgomp.so.1
is part of the Intel libraries, you can try unloading thegcc
module withmodule unload gcc
if it is loaded, or reloading theintel
module withmodule load intel
. -
Error message:
slurmstepd: error: Detected zonesort setup failure: Could not open job cpuset (########.#)
Possible causes/remedies:
KNL's MCDRAM cache is prone to cache thrashing because it uses direct mapped caching, which can result in slow code performance. To alleviate this possibility, the system's Node Health Check tool runs the 'zonesort' kernel module on compute nodes. For more info, please see KNL Cache Mode. Note that the zonesort module is also run on Haswell nodes although performance implication may not be as significant since direct mapped caching is not used.
The error message means that running the zonesort kernel failed for some reason. The end result is that your code may have run less optimally. Other than that, the message is usually harmless. If your job failed because the application ran slowly, please resubmit the job.
-
Error message:
slurmstepd: error: _is_a_lwp: open() /proc/XXXXX/status failed: No such file or directory
Possible causes/remedies:
_is_a_lwp
is a function called internally for Slurm job accounting. The message indicates a rare error situation with a function call. But the error shouldn't affect anything in the user job. Please ignore the message. -
Error messages mentioning problems when "locking files", e.g.:
Programs built against the Cray HDF5 or NetCDF libraries may break due to a known bug in a file locking feature: see the known issues section of the HDF5 docs page.
-
Error message when copying files to Burst Buffer:
cp: error writing '/var/opt/cray/dws/mounts/batch/YourPersistentReservation/a_file': Read-only file system
or in a Python program:
Traceback (most recent call last): ... OSError: [Errno 30] Read-only file system
Too many writes have been performed in your Burst Buffer allocation, which triggered the write protection of the underlying SSDs and made the file system read-only, to avoid drive blocks to wear out too quickly.
If you are using a Burst Buffer allocation and need to access the same files from multiple jobs, consider using a Persistent Reservation (PR): no backup is performed of data on Burst Buffer, so always stage-out/copy the important files. See the related page on Burst Buffer.
The solution is to either wait some hours for the SSDs to "cooldown", or request a new and bigger PR (remember that resources are limited and other users may also need storage space).